1. Field of the Invention
The present invention relates to a low recoil firearm. In particular, the present invention relates to a low coil firearm having a counterweight.
2. Description of the Related Art
In an automatic gun, a barrel and a bolt are moved backward to load the next bullet by using firing gas pressure generated when shooting a bullet. Since large impact is generated when the barrel and the bolt are moved backward, Patent document 1 discloses a gun (low recoil firearm) that reduces the recoil by driving a counterweight in an opposite direction, for example.
The recoil generated when shooting the bullet in the low recoil firearm is shown in FIG. 25 and FIG. 26.
FIG. 25 is a schematic view showing a configuration of a low recoil firearm invented by the inventor of the present invention. FIG. 26 is a schematic view showing a principle of misalignment of the trajectory of the bullet in the low recoil firearm.
A bolt 2 is located on the back side (left side in the figure) of a barrel 1. Immediately after the bullet is shot, the barrel 1 and the bolt 2 are integratedly moved backward by receiving the pressure of the firing gas. A not illustrated rack is formed on an upper surface of the barrel 1 so that the rack is engaged with a gear 3. The gear 3 is rotatably supported at a fixed position. At an upper surface side of the gear 3, the gear 3 is engaged with a not illustrated rack formed on a lower surface of a counterweight 4.
When the barrel 1 and the bolt 2 are moved backward, the gear 3 is rotated clockwise and the counterweight 4 is moved forward. In other words, the recoil generated when the barrel 1 and the bolt 2 are moved backward functions as a power source to drive the counterweight 4 forward. Consequently, the recoil to the holder of the gun is resolved.
The barrel 1 is moved together with the bolt 2 because the discharge of the firing gas should be delayed with respect to the timing of shooting the bullet. Therefore, the firing gas should be sealed in the barrel 1 for a certain period of time. For the certain period of time, although it is short, the barrel 1 should be moved together. For this reason, a barrel supporting member 5 is required to support the barrel 1 itself so as to be movable back and forth. A clearance is required between the barrel supporting member 5 and the barrel 1 so that the barrel 1 is moved smoothly.
In a short-recoil system which is very often used in recent years, the barrel 1 is specified to be tilted when discharging the firing gas after the shooting. In this system, the clearance is relatively large because the barrel 1 should be tilted.
[Patent Document 1] U.S. patent application publication No. 2010/0088942